Thuja occidentalis

Superregnum: Eukaryota
Regnum: Plantae
Divisio: Tracheophyta
Divisio: Pinophyta
Classis: Pinopsida
Ordo: Pinales

Familia: Cupressaceae
Subfamilia: Cupressoideae
Genus: Thuja
Species: Thuja occidentalis
Name

Thuja occidentalis L., Sp. Pl. 2: 1002 (1753).
Synonyms

Homotypic
Thuja procera Salisb., Prodr. Stirp. Chap. Allerton: 398 (1796), nom. superfl.
Thuja theophrasti Nieuwl., Amer. Midl. Naturalist 2: 284 (1912), nom. superfl.
Heterotypic
Thuja occidentalis var. variegata Weston, Bot. Univ. 1: 294 (1770)
Thuja odorata Marshall, Arbust. Amer.: 152 (1785)
Thuja variegata Marshall, Arbust. Amer.: 152 (1785)
Thuja obtusa Moench, Methodus: 691 (1794)
Cupressus arborvitae O.Targ.Tozz., Ann. Mus. Imp. Fis. Firenze, reimpr. 3-5: 71 (1810)
Thuja nana Carrière, Traité Gén. Conif.: 93 (1855), pro syn.
Thuja occidentalis var. compacta Carrière, Traité Gén. Conif.: 104 (1855)
Thuja occidentalis var. robusta Carrière, Traité Gén. Conif.: 104 (1855)
Thuja occidentalis var. variegata-aurea Carrière in H.A.Jacques & F.Hérincq, Man. Gén. Pl. 4: 323 (1857)
Thuja caucasica Gordon, Pinetum, Suppl.: 103 (1862)
Thuja compacta Standish ex Gordon, Pinetum, Suppl.: 103 (1862)
Thuja ericoides Gordon, Pinetum, Suppl.: 91 (1862).
Thuja occidentalis var. pendula Gordon, Pinetum, Suppl.: 103 (1862)
Thuja sibirica Gordon, Pinetum, Suppl.: 104 (1862)
Thuja tatarica Gordon, Pinetum, Suppl.: 104 (1862)
Thuja vervaeneana Van Geert ex Gordon, Pinetum, Suppl.: 103 (1862)
Thuja recurvata-nana Stelzner, Cat. 5: ? (1863)
Thuja occidentalis var. aureovariegata Henkel & W.Hochst., Syn. Nadelhölz.: 279 (1865)
Thuja occidentalis var. fastigiata H.Jaeger, Ziergehölze Gärt. Parkanl.: 537 (1865)
Thuja occidentalis var. aurea J.Nelson, Pinaceae: 68 (1866)
Thuja occidentalis pendula-variegata J.Nelson, Pinaceae: 68 (1866)
Thuja sibirica var. pendula (Gordon) J.Nelson, Pinaceae: 68 (1866)
Chamaecyparis boursieri Carrière, Traité Gén. Conif., ed. 2: 125 (1867), nom. illeg.
Retinispora dubia Carrière, Traité Gén. Conif., ed. 2: 141 (1867)
Retinispora meldensis Carrière, Traité Gén. Conif., ed. 2: 103 (1867)
Thuja devriesiana Carrière, Traité Gén. Conif., ed. 2: 141 (1867), pro syn.
Thuja minor Carrière, Traité Gén. Conif., ed. 2: 110 (1867), pro syn.
Thuja occidentalis var. cristata Carrière, Traité Gén. Conif., ed. 2: 111 (1867)
Thuja occidentalis ericoides C.Lawson, Ill. Farmer Gard. Alman. 1867: 102 (1867)
Thuja occidentalis pumila Ed.Otto, Hamburger Garten- Blumenzeitung 23: 162 (1867)
Thuja occidentalis var. hoveyi Hoopes, Book Evergr.: 322 (1868)
Retinispora ellwangeriana Carrière, Rev. Hort. (Paris) 41: 349 (1869)
Thuja ellwangeriana Carrière, Rev. Hort. (Paris) 41: 350 (1869)
Thuja triangularis Defresne ex Beer, Ber. Welt-Austell. Paris 5: 36 (1869)
Thuja canadensis K.Koch, Dendrologie 2(2): 175 (1873)
Thuja hoveyi Gordon, Pinetum, ed. 2: 405 (1875)
Thuja occidentalis var. alba Maxwell ex Gordon, Pinetum, ed. 2: 431 (1875)
Thuja occidentalis var. globosa Gordon, Pinetum, ed. 2: 405 (1875)
Thuja occidentalis var. vervaeneana Gordon, Pinetum, ed. 2: 406 (1875)
Thuja plicata var. pendula (Gordon) Gordon, Pinetum, ed. 2: 431 (1875), pro syn.
Cupressus nobleana (Beissn.) Lavallée, Énum. Arbres: 282 (1877)
Thuja wareana var. lutea Van Geert, Nursery Cat. (Auguste Van Geert) 76: 27 (1878)
Juniperus ericoides Mast., J. Linn. Soc., Bot. 18: 495 (1881)
Retinispora devriesiana Mast., J. Linn. Soc., Bot. 18: 495 (1881)
Thuja occidentalis var. lutea A.H.Kent in H.J.Veitch, Man. Conif.: 262 (1881)
Thuja occidentalis var. magnifica Beissn. in H.Jaeger & L.Beissner, Ziergehölze Gärt. Parkanl., ed. 2: 500 (1884)
Thuja occidentalis var. rosenthalii Beissn. in H.Jaeger & L.Beissner, Ziergehölze Gärt. Parkanl., ed. 2: 500 (1884)
Thuja occidentalis f. aurea (J.Nelson) Beissn., Handb. Conif.: 8 (1887)
Thuja occidentalis f. aureovariegata (Henkel & W.Hochst.) Beissn., Handb. Conif.: 30 (1887)
Thuja occidentalis f. ellwangeriana (Carrière) Beissn., Handb. Conif.: 6 (1887)
Thuja occidentalis f. ericoides (C.Lawson) Beissn., Handb. Conif.: 6 (1887)
Thuja occidentalis f. fastigiata (H.Jaeger) Beissn., Handb. Conif.: 8 (1887)
Thuja occidentalis f. globosa (Gordon) Beissn., Handb. Conif.: 8 (1887)
Thuja occidentalis f. hoveyi (Hoopes) Beissn., Handb. Conif.: 8 (1887)
Thuja occidentalis f. ohlendorffii Beissn., Handb. Conif.: 28 (1887)
Thuja occidentalis f. vervaeneana (Gordon) Beissn., Handb. Conif.: 8 (1887)
Retinispora troubetzkoyana auct., Gard. Chron., ser. 3, 7: 108 (1890)
Retinispora glaucescens Hochst. ex Beissn., Handb. Nadelholzk.: 35 (1891)
Retinispora keteleeri Beissn., Handb. Nadelholzk.: 95 (1891)
Retinispora nobleana Beissn., Handb. Nadelholzk.: 94 (1891)
Retinispora pygmaea Beissn., Handb. Nadelholzk.: 97 (1891)
Thuja bodmeri Beissn., Handb. Nadelholzk.: 42 (1891)
Thuja globosa Beissn., Handb. Nadelholzk.: 43 (1891)
Thuja occidentalis var. buchananii Späth, Preiss-Verzeichn. Pflanzen. 89: 51 (1891)
Thuja occidentalis var. douglasii-pyramidalis Späth, Preiss-Verzeichn. Pflanzen. 89: 51 (1891)
Thuja occidentalis f. filicoides Beissn., Handb. Nadelholzk.: 43 (1891)
Thuja occidentalis f. pendula (Gordon) Beissn., Handb. Laubholzk.: 42 (1891)
Thuja occidentalis f. pendula-glauca Beissn., Handb. Laubholzk.: 42 (1891)
Thuja occidentalis f. recurva-nana Beissn., Handb. Nadelholzk.: 42 (1891)
Thuja occidentalis f. recurvata Beissn., Handb. Nadelholzk.: 42 (1891)
Thuja occidentalis f. riversii Beissn., Handb. Nadelholzk.: 41 (1891)
Thuja occidentalis var. umbraculifera Beissn., Möller's Deutsche Gärtn.-Zeitung 6: 179 (1891)
Thuja occidentalis f. viridis Beissn., Handb. Nadelholzk.: 41 (1891)
Thuja occidentalis f. wareana-lutescens Beissn., Handb. Nadelholzk.: 40 (1891)
Thuja occidentalis var. woodwardii Späth, Preiss-Verzeichn. Pflanzen. 89: 51 (1891)
Thuja occidentalis var. plicata Mast., Gard. Chron., ser. 3, 21: 258 (1897), nom. illeg.
Thuja occidentalis var. filiformis Beissn., Mitt. Deutsch. Dendrol. Ges. 10: 81 (1901)
Thuja occidentalis var. douglasii Rehder in L.H.Bailey, Cycl. Amer. Hort. 4: 1802 (1902)
Thuja occidentalis f. buchananii (Späth) Beissn., Handb. Nadelholzk., ed. 2: 506 (1909)
Thuja occidentalis f. alba (Maxwell ex Gordon) C.K.Schneid. in E.E.Silva Tarouca, Uns. Freil.-Nadelhölzer: 284 (1913)
Thuja occidentalis f. cristata (Carrière) C.K.Schneid. in E.E.Silva Tarouca, Uns. Freil.-Nadelhölzer: 282 (1913)
Thuja occidentalis f. lutea (A.H.Kent) C.K.Schneid. in E.E.Silva Tarouca, Uns. Freil.-Nadelhölzer: 283 (1913)
Thuja occidentalis f. rosenthalii (Beissn.) C.K.Schneid. in E.E.Silva Tarouca, Uns. Freil.-Nadelhölzer: 281 (1913)
Thuja occidentalis var. squarrosa C.K.Schneid. in E.E.Silva Tarouca, Uns. Freil.-Nadelhölzer: 281 (1913)
Thuja occidentalis f. umbraculifera (Beissn.) C.K.Schneid. in E.E.Silva Tarouca, Uns. Freil.-Nadelhölzer: 281 (1913)
Thuja occidentalis var. sempervirens Rehder in L.H.Bailey, Cult. Evergreens: 223 (1923)
Thuja occidentalis f. mastersii Rehder, J. Arnold Arbor. 20: 87 (1939)
Thuja occidentalis f. gaspensis Vict. & J.Rousseau, Contr. Inst. Bot. Univ. Montréal 36: 11 (1940)
Thuja occidentalis f. prostrata Vict. & J.Rousseau, Contr. Inst. Bot. Univ. Montréal 36: 9 (1940)
Thuja occidentalis f. compacta (Carrière) Rehder, Bibl. Cult. Trees: 46 (1949)
Thuja occidentalis f. filiformis (Beissn.) Rehder, Bibl. Cult. Trees: 46 (1949)
Thuja occidentalis f. magnifica (Beissn.) Rehder, Bibl. Cult. Trees: 46 (1949)
Thuja occidentalis f. pumila (Otto) Rehder, Bibl. Cult. Trees: 46 (1949)
Thuja occidentalis f. robusta (Carrière) Rehder, Bibl. Cult. Trees: 45 (1949)
Thuja occidentalis f. sempervirens (Rehder) Rehder, Bibl. Cult. Trees: 45 (1949)
Thuja occidentalis f. variegata (Weston) Rehder, Bibl. Cult. Trees: 45 (1949)
Thuja occidentalis f. woodwardii (Späth) Rehder, Bibl. Cult. Trees: 46 (1949)

References

Linnaeus, C. 1753. Species Plantarum. Tomus II: 1002. Reference page.
Govaerts, R. et al. 2017. Thuja occidentalis in World Checklist of Selected Plant Families. The Board of Trustees of the Royal Botanic Gardens, Kew. Published online. Accessed: 2017 Aug. 15. Reference page.
International Plant Names Index. 2017. Thuja occidentalis. Published online. Accessed: Aug. 15 2017.

Vernacular names
беларуская: Туя заходняя
čeština: Zerav západní
Deutsch: Abendländischer Lebensbaum
English: Northern White-cedar
Esperanto: Okcidenta tujo
eesti: Harilik elupuu
suomi: Kanadantuija
français: Thuya occidental
hrvatski: Tuja
magyar: Nyugati tuja
italiano: Tuia occidentale
lietuvių: Vakarinė tuja
polski: Żywotnik zachodni
русский: Туя западная
svenska: Tuja
Türkçe: Batı mazısı

Thuja occidentalis, also known as northern white-cedar,[1] eastern white-cedar,[2] or arborvitae,[2][3] is an evergreen coniferous tree, in the cypress family Cupressaceae, which is native to eastern Canada and much of the north-central and northeastern United States.[3][4] It is widely cultivated as an ornamental plant.

Common names

Its additional common names include swamp cedar,[3] American arborvitae,[4] and eastern arborvitae.[4] The name arborvitae is particularly used in the horticultural trade in the United States; it is Latin for 'tree of life' – due to the supposed medicinal properties of the sap, bark, and twigs.[5] It is sometimes called white-cedar (hyphenated) or whitecedar (one word)[4] to distinguish it from Cedrus, a distantly related genus of trees also known as cedars.[6]
Description

Unlike the closely related western red cedar (Thuja plicata), northern white cedar is only a small or medium-sized tree, growing to a height of 15 m (49 ft) tall with a 0.9 m (3.0 ft) trunk diameter, exceptionally to 38 metres (125 ft) tall and 1.8 metres (5.9 ft) diameter.[7] The tree is often stunted or prostrate in less favorable locations. The bark is red-brown, furrowed and peels in narrow, longitudinal strips. Northern white cedar has fan-like branches and scaly leaves. The foliage forms in flat sprays with scale-like leaves 3–5 millimetres (1⁄8–3⁄16 in) long.

The seed cones are slender, yellow-green, ripening to brown, 9–14 millimetres (3⁄8–9⁄16 in) long and 4–5 millimetres (5⁄32–3⁄16 in) broad,[citation needed] with six to eight overlapping scales. They contain about eight seeds each.[7] The branches may take root if the tree falls.[4]

Taxonomy

The species was first described by Carl Linnaeus in 1753. Over 30 synonyms are listed in Kew's Plants of the World Online database.[8]
Distribution

Northern white cedar is native to an area in the southern part of eastern Canada and the adjacent part of the northern United States. It extends from southeastern Manitoba east throughout the Great Lakes region and into Ontario, Québec, New York, Vermont, New Hampshire, Maine, Prince Edward Island, New Brunswick, and Nova Scotia. Isolated populations occur in west-central Manitoba, and to the south in Massachusetts, Connecticut, Ohio, and Illinois and in the Appalachian Mountains of Kentucky, Tennessee, North Carolina, Pennsylvania, Maryland, Virginia, and West Virginia.[4] In Canada, its range reaches the Arctic treeline and the southern tip of Hudson Bay. It grows mainly in places with cooler summers, with a typical temperature of 16 to 22 °C (61 to 72 °F) in July, and a shorter growing season, from 90 to 180 days.[9]
Ecology
A swamp along the Superior Hiking Trail in November with white cedars (left) and other trees and shrubs

Northern white cedar grows naturally in wet forests, being particularly abundant in coniferous swamps, where other larger and faster-growing trees cannot compete successfully. It also occurs on other sites with reduced tree competition, such as cliffs. Although not currently listed as endangered, wild white cedar populations are threatened in many areas by high deer numbers; deer find the soft evergreen foliage a very attractive winter food and strip it rapidly. The largest known specimen is 34 m (112 ft) tall and 175 cm (69 in) diameter, on South Manitou Island within Leelanau County, Michigan.[citation needed] Northern white cedars can be very long-lived trees in certain conditions, with notably old specimens growing on cliffs where they are inaccessible to deer and wildfire. As of 2008, the oldest known living specimen was 1,141 years old,[10] but a dead specimen with 1,653 growth rings has been found.[11] Despite their age, these very old trees are small and stunted due to the difficult growing conditions. These individuals' long lifespans have been attributed to their slow growth and their ability to survive when different sections of the tree are damaged or killed.[12] The Witch Tree, a T. occidentalis growing out of a cliff face on Lake Superior in Minnesota, was described by the French explorer Sieur de la Verendrye as being a mature tree in 1731; it is still alive today.
Old trees growing on a rock ledge in Potawatomi State Park, Wisconsin

Specimens found growing on cliff faces in southern Ontario are the oldest trees in Eastern North America and all of Canada, having achieved ages in excess of 1,653 years.[4]
Uses

Thuja occidentalis is a tree with important uses in traditional Ojibwe culture. Honored with the name Nookomis Giizhik (Grandmother Cedar), the tree is the subject of sacred legends and is considered a gift to humanity for its myriad of uses, among them crafts, construction, and medicine.[13] It is one of the four plants of the Ojibwe medicine wheel, associated with the north. The foliage is rich in vitamin C and is believed to be the annedda, which cured the scurvy of Jacques Cartier and his party in the winter of 1535–1536.[9] Due to the presence of the neurotoxic compound thujone, internal use can be harmful if used for prolonged periods or while pregnant.[citation needed] It is commercially used for rustic fencing and posts, lumber, poles, shingles, and in the construction of log cabins.[9] It is the preferred wood for the structural elements, such as ribs and planking, of birchbark canoes and the planking of wooden canoes.[14]

The essential oil within the plant has been used for cleansers, disinfectants, hair preparations, insecticides, liniment, room sprays, and soft soaps. The Ojibwa reportedly made a soup from the inner bark of the soft twigs. Others have used the twigs to make teas to relieve constipation and headache.[14]
Cultivation
A grove of a columnar ornamental variety in Powsin Botanical Garden, Warsaw, Poland

T. occidentalis is widely used as an ornamental tree, particularly for screens and hedges, in gardens, parks, and cemeteries. Over 300 cultivars exist, showing great variation in colour, shape, and size, with some of the more common ones being 'Degroot's Spire', 'Ellwangeriana', 'Hetz Wintergreen', 'Lutea', 'Rheingold', 'Smaragd' (or 'Emerald Green'), 'Techny', and 'Wareana'. It was introduced into Europe as early as 1540.[citation needed] These cultivars have gained the Royal Horticultural Society's Award of Garden Merit:

'Danica',[15]
'Golden Tuffet'[16]
'Holmstrup',[17]
'Rheingold',[18]
'Smaragd'.[19]

References

Farjon, A. (2013). "Thuja occidentalis". IUCN Red List of Threatened Species. 2013: e.T42262A2967995. doi:10.2305/IUCN.UK.2013-1.RLTS.T42262A2967995.en.
Brouillet L. et al. 2010+. "Thuja occidentalis Linnaeus". data.canadensys.net. Database of Vascular Plants of Canada (VASCAN). Retrieved 3 October 2020.
"Thuja occidentalis". Germplasm Resources Information Network (GRIN). Agricultural Research Service (ARS), United States Department of Agriculture (USDA).
Earle, Christopher J., ed. (2018). "Thuja occidentalis". The Gymnosperm Database.
Thuja, American Cancer Society, last revised 6/19/2007. available online
"The Cedars" (PDF). 2004.
Chambers, Kenton L. (1993). "Thuja occidentalis". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 2. New York and Oxford. Retrieved 24 September 2016 – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
"Thuja occidentalis L." Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 3 October 2020.
Johnston, William F. (1990). "Thuja occidentalis". In Burns, Russell M.; Honkala, Barbara H. (eds.). Conifers. Silvics of North America. Washington, D.C.: United States Forest Service (USFS), United States Department of Agriculture (USDA). Vol. 1 – via Southern Research Station.
"Eastern OLDLIST. Thuja occidentalis". Rocky Mountain Tree-Ring Research, Inc. & Eastern Kentucky University. 2008. Retrieved 15 January 2021.
"Eastern OLDLIST a database of ancient trees and their ages". Rocky Mountain Tree-Ring Research, Inc. & Eastern Kentucky University. 2020. Retrieved 15 January 2021.
Larson, D.W. (2001). "The paradox of great longevity in a short-lived tree species". Experimental Gerontology. 36 (4–6): 651–673. doi:10.1016/S0531-5565(00)00233-3. ISSN 0531-5565. PMID 11295506. S2CID 24297929.
Geniusz, Wendy Makoons (2009). Our Knowledge is not Primitive. Syracuse, NY: Syracuse University Press
"USDA/NRCS Plant Guide: Northern White Cedar, Thuja occidentalis L." (PDF). United States Department of Agriculture. Retrieved 2008-02-15.
"RHS Plant Selector – Thuja occidentalis 'Danica'". RHS. Retrieved 5 March 2021.
"Thuja occidentalis 'Golden Tuffet'". RHS. Retrieved 5 March 2021.
"RHS Plant Selector – Thuja occidentalis 'Holmstrup'". RHS. Retrieved 5 March 2021.
"RHS Plant Selector – Thuja occidentalis 'Rheingold'". RHS. Retrieved 5 March 2021.
"RHS Plant Selector – Thuja occidentalis 'Smaragd'". RHS. Retrieved 5 March 2021.